UI:

* Added very basic loading of .py files on startup to define panels.
  It now executes all .py files in .blender/ui on startup. Right now
  this contains the object buttons, the C code for it is commented out.

  These files should get embedded in the blender executable as well
  eventually, that's a bit more complicated so this works for now.

* For scons and cmake it seems to copy & find the files OK, for make
  only "make release" works (same with scripts/ folder it seems).

* Added BLI_gethome_folder function in BLI_util.h. This is adapted
  from bpy_gethome, and gives the path to a folder in .blender like
  scripts or ui.

There's plenty of things to figure out here about paths, embedding,
caching, user configs ...

source/blender/python/BPY_extern.h

@@ -99,6 +99,7 @@ extern "C" {
 	/* 2.5 UI Scripts */
 	int BPY_run_python_script( struct bContext *C, const char *filename, struct Text *text ); // 2.5 working
 	int BPY_run_script_space_draw(struct bContext *C, struct SpaceScript * sc); // 2.5 working
+	void BPY_run_ui_scripts(struct bContext *C);
 //	int BPY_run_script_space_listener(struct bContext *C, struct SpaceScript * sc, struct ARegion *ar, struct wmNotifier *wmn); // 2.5 working